The present invention relates to a seamless annular resin molded article for use in a liner within a chamber of a dry etching apparatus used in semiconductor manufacture. More specifically, the invention relates to a resin molded article for a liner, which resin molded article is able to reduce, for an extended period of time, damage to circuits formed on wafers owing to contamination within the liner by heavy metals or reaction products, and the fitting method for which is simple.
A dry etching process that uses plasma has been employed recently in semiconductor manufacture. In this plasma dry etching process, a reactive gas is ionized with a plasma, the ionized gas is induced to react chemically with the material to be etched, and the etched material is removed together with the gas. However, the direction of etching has isotropy, which results in wafer contamination by heavy metals due to sputtering and etching of the liner installed within the chamber in the dry etching apparatus. Alumite-treated aluminum liners have been used to prevent this.
Unfortunately, under severe plasma irradiation conditions, the surface layer of alumite detaches in a relatively short time, resulting in wafer contamination by aluminum particles.
Moreover, to prevent the deposition on the wafer of that portion of the reaction products formed by dry etching which is not discharged as gases but remains instead within the liner, a liner having a construction in which the reaction products deposit on the liner inside wall by heating the liner from the outside, maintaining the liner inside wall at a predetermined temperature, and thus controlling agglomeration of the reaction product is used. Yet, it could not be sufficient to adequately prevent contamination of the wafer by the reaction products.
To prevent wafer contamination by aluminum particles and reaction products, there has been developed an alumite-treated aluminum liner coated on the inside wall with a dispersion of a polyimide precursor having excellent plasma resistance. However, the applied coat lacks sufficient durability and plasma resistance, and cannot be thickly applied.
Liners are used with a polyimide film obtained from a polyimide precursor, but their durability and plasma resistance are not sufficient, in addition to which a film thickness greater than 0.25 mm cannot be achieved. Moreover, reaction products deposit locally at seams and deposit excessively even when the temperature of the liner inside wall is controlled, which causes the detachment of deposits, resulting in contamination within the liner. Moreover, the film has a tendency to peel off starting at seams. In addition, since an adhesive is used to fit the film to the inside wall of the liner, replacement of the film cannot be easily carried out.
Hence, a need exists for a resin molded article for liners which is able to reduce, for an extended period of time, damages to circuits formed on wafers due to contamination within the liner by heavy metals and reaction products, and which is easy to fit in place and easy to remove.
In is therefore an object of this invention to provide a resin molded article for a liner, which article has excellent plasma resistance and durability, and is also easy to fit into place and easy to remove.
We have conducted extensive research to resolve problems such as these. As a result, we have found that damage to the circuits formed on wafers due to contamination within the liner by heavy metals and reaction products can be reduced for an extended period of time by fitting to the inside wall of the liner a seamless (annular or ring-shaped resin molded article having plasma resistance, heat resistance, flexibility, and a predetermined thickness.
Accordingly, a first aspect of the present invention relates to a resin molded article for fitting to an inside wall of a liner in a chamber of a dry etching apparatus used in semiconductor manufacture, wherein the resin molded article is a seamless annular molded article having a heat resistance temperature of at least 100xc2x0 C., a tensile elongation at break of at least 0.3%, a flexural modulus of at least 10,000 kg/cm2, an outside diameter from 0 to 0.3% larger than the inside diameter of the liner, and a wall thickness of not more than 2 mm.
A second aspect of the invention relates to the above-described resin molded article, wherein the resin molded article is a seamless annular molded article having a heat resistance temperature of at least 100xc2x0 C., a tensile elongation at break of at least 5%, a flexural modulus within a range of 10,000 to 100,000 kg/cm2, an outside diameter from 0.01 to 0.3% larger than the inside diameter of the liner, and a wall thickness of not more than 2 mm.
A third aspect of this invention relates to a resin molded article for fitting to an inside wall of a liner in a chamber of a dry etching apparatus used in semiconductor fabrication, wherein the resin molded article is a seamless annular molded article which is molded of polyimide resin powder and which has an outside diameter from 0.01 to 0.3% larger than the inside diameter of the liner and a wall thickness of not more than 2 mm.